Scientists at NASA's Jet Propulsion Laboratory have announced the discovery of a nearby explanet called UCF-1.01 — a planet so blazingly hot, it's likely covered in hot magma. And at 33 light years away, this is the closest planet we've discovered that is smaller than Earth.

The discovery is another example of our enhanced ability to detect distant objects that are not just smaller than gas giants, but even smaller than our own planet.

The exoplanet was discovered by NASA astronomer Kevin Stevenson who, along with his team, were using the Spitzer space-based telescope. They had been observing a Neptune-like planet in the GJ 436 solar system when they started to notice some intermittent dimming. Looking more closely at the data, the astronomers concluded that the dips were periodic — a sign that a planet is very likely present.

Their conclusions were recently accepted for publication in The Astrophysical Journal.

According to Stevenson, the planet is about 5,200 miles in diameter (8,400 kilometers) which is two-thirds the size of Earth. It's revolving quite tightly around its red-dwarf parent star; it's only 1,672,300 miles (384,400 kilometers) from its sun, which is about about seven times the distance of the Earth to the moon. Its year only lasts about 1.4 Earth days. And because UCF-1.01 is so close to its sun, its surface temperature is an excruciatingly hot 600 degrees Celsius, leading the NASA researchers to speculate that it's covered in magma.

The scientists also cautiously note that they believe two other planets reside in the same solar system, but they need to conduct more research to prove it.

Discoveries such as this one are exceptionally rare. Of the nearly 1,800 candidate stars identified by NASA's Kepler space telescope, only three have been confirmed as having sub-Earth exoplanets in their orbit. And of these, only one is smaller than UCF-1.01.